Top Voted Answer

Ultima is best learned at the front gates of Limberry where you fight the assassins WITHOUT elmdor around.

Bring along Judo Outfits and Jade Armlets, I believe, and this will protect you against their worst attacks so they'll usually cast Ultima if they can't cast Stop Bracelet nor Shadow Stitch. Bring 108 Gems for the next fight where you'll outright kill them AND steal all of Elmdor's Genji equipment.

As for Zodiac, I suggest having Malak learn it during the initial fight, and I believe you can fight Summoner units in earlier floors. Bring along someone with Talk Skill and lower their Faith stats greatly. Combine Malak's low Faith and they should survive the attack and this will allow you to tranfer the spell to 4 other characters during the fight.

In order for Ramza to learn Ultima one of the assassins that are with Elmdor must cast it on him during chapter 4. It's a tricky proposition, I recommend wearing 108 gems in order to encourage them to use that as opposed to their deadly hand skills.